Recently, as an importance of security is getting higher, a variety of security programs are used, and a variety of security programs are also being developed. In addition, in case of sharing personal information or copyrighted works, a risk of information leakage is increased; thus, an importance of security programs is continually being increased.
One of methods for managing a file is done by managing an access to database. In relation to the method for managing the file, Korean registered Patent No. 10-1158336 (published on Jun. 22, 2012) discloses a method that is able to handle a copy, move, inquiry and delete of personal information solely according to an authorization assigned to each virtual directory.
Merely, in providing a service for managing a file, when it is not able for a user to delete a re-distributed content linked on SNS, and it is not able for a user to be directly deleted by the user him/herself according to a change of human relationship on SNS even though the content has been uploaded by the user him/herself, the user directly involved cannot delete it in spite of his/her desire. Moreover, unless file itself is deleted, if a database is hacked, the relevant file may be leaked, and when a copyrighted file is shared, in a digital environment that copy and save is easy, it cannot exclude a possibility that the file may be re-distributed by a user who has not copyright to the relevant file.